Barney [dressed in old man costume]: In a few minutes, the young me from your time is going to come through that door. Now, Cindy, I know this sounds insane, but in order to save the planet, you need to sleep with him tonight.Cindy: What? I...Barney: Sleep with Barney Stinson tonight, in whatever way he wants it, or he won't be able to find the solution to global warming that saves the human race